As to pneumatic devices, the sealing performance directly affects its working, and the friction characteristics between seal ring and cylinder affect stability of reciprocated movement of the piston. Two dimensional (2D) axisymmetric finite element analysis (FEA) contact model was built in ANSYS software, and the static and dynamic seal performance of Oring with cylinder were studied separately. The effects law of precompression rate, working medium pressure and friction coefficient on sealing performance were obtained. Builting the friction characteristics test experiment platform, making characteristics test of the maximum static friction force, dynamic friction under noload, dynamic friction under load, the effects law of working medium pressure and velocity on the friction characteristics were obtained.